Method for dyeing glass fibers and product thereof

ABSTRACT

Glass fibers are coronized and then contacted with aqueous chromic acid. The chromic acid treatment increases the surface area of the fibers and deposits chromate ions on their surface. The treated fibers are washed to remove excess chromate ions, dyed with a cationic or mordant dye and then overcoated with a suitable material, e.g., a plastic or elastomeric film or a chrome complex.

[72] Inventors Siegfried K. June [56] References Cited Nev/FY11; UNITEDSTATES PATENTS Neely 2,582,919 1/1952 Biefeld 8/8 x [21] Appl. No.702,801

2,593,818 4/1952 Waggoner.. 117/126 X [22] 2 754 224 7/1956 Caroselli117/126 x [45] Patented Nov. 2, 1971 [73] Assignee 115.11. du Pont deNemours and Company OTHER REFERENHCES Wilmington, Del. Jones, Inorg.Chem., 1949, p. 672 Moeller, lnorgv Chem.

Schlesinger, Gen. Chem., 1938,p. 769

Primary Examiner Donald Levy Assistant Examiner- Patricia C. lves 154111121111011) FOR DYEING GLASS FIBERS AND Nome-Lynn PRODUCT THEREOF 11ClalmsNo Drawings ABSTRACT: Glass fibers are coronized and thencontacted [52] U.S.C1 8/8, wi h aqueous hr m i Th hr mi i r m n in-8/18, 65/30, 117/126, 134/3 creases the surface area of the fibers anddeposits chromate [51] 1111.131 ..C03c 17/00, n on their surface Thetreated fibers are washed to remove D06p 3/80 excess Chromate ions, dyedwith a cationic or mordant dye [50] Field of Search 8/8, 18; and then oer t a suitable material -g-, plastic or elastomeric film or a chromecomplex.

METHOD FOR DYEING GLASS FIBERS AND PRODUCT THEREOF BACKGROUND OF THEINVENTION Glass fibers have been very difficult to dye because of theirphysical and chemical properties. Among other things these fibers havesmooth surfaces and are relatively inert in comparison with organictextile fibers.

Many methods have been proposed; one that is in use involves coatingglass fabrics with resin containing dispersed dyes. Such fabrics arestiff and have poor laundry and dry cleaning resistance, further thecolors produced are not very bright. Thus such fabrics are not generallyused for such items as bedspreads, tablecloths and clothing.

of the many direct dyeing methods that have been proposed, such as theprocess of U.S. Pat. No. 2,582,9l9, none are commercially satisfactory.

SUMMARY OF THE lNVENTlON This invention is directed to glass fibers,filaments, yarns or fabrics which can be readily dyed and to theprocesses for dyeing such fibers, filaments, yarns or fabrics.

The glass fibers of the invention are fibers which have been treatedwith a heated 0.1 to 50 percent aqueous solution of chromic acid for aperiod of time to increase their surface area and to deposit chromateions of their surface.

These glass fibers are washed to remove the excess chromic acid and thendyed with cationic (basic) dyes or, in a less preferred embodiment, withmordant type dyes. The dyed fiber can then be overcoated with variousmaterials, e.g., plastics, elastomers, resinous type materials or chromecomplexes.

The resulting fibers form fabrics which are uniformly dyed, brightlycolored, with good hand and fastness to light, and good resistance tolaundering, crocking and drycleanin g.

DETAILED DESCRIPTION OF THE INVENTION The glass fibers useful in theinvention are both nonborosilicate glass fibers and borosilicate glassfibers, and particularly the latter. The particularconstituents of thefibers are not critical, and any of the glass fibers presently in usecan be treated according to the invention.

The fiber can be treated according to the invention while in the form ofa single fiber, strand, filament, or when in the form of woven orunwoven fabrics. The use of the term fiber" hereinafter is intended tocover all of these various physical forms.

In the making of glass fibers, the fibers are generally coated with anoily, greasy or waxy material in order to prevent abrasion. Thesecoatings can create problems in the treating of the fibers. Thusnormally it will be desirable to remove these coatings prior totreatment. This can be accomplished by use of a suitable solvent, butusually it will be accomplished by coronizing. Coronizing consists ofheat treating and crimping the fibers at a temperature of about 1200 F.until the coating is removed.

The uncoated glass fiber is then treated with heated, aqueous chromicacid.

This treatment accomplishes two results; first, it leaches out variousnonsiliceous components ofthe fiber, e.g., boron, aluminum, and sodiummetal ions and also the oxides of these metals. This leaching results ina macroporous surface having increased surface area. Under mostconditions it will be found that about a percent by weight loss iscaused by the leaching step. This, of course, reduces to some extent thestrength of the fiber, but not enough to detract from its usefulness.

Secondly, the treatment deposits chromate ions on the macroporoussurface of the fiber, thus creating a negatively charged surface.

Although applicant does not mean to be bound by the following theory, itis his belief that the chromate ions are held on to the surface of theglass by the formation of a Si-O-Cr bond. However, it is possible thatthe chromate ions are held on the surface merely by electrostaticbonding. In any event, the chromate is held on the surface and does notwash off.

This combination of increased surface area and chromate ions present onthe surface creates a reactive surface that is very receptive tocationic type dyes. The surface is also receptive to mordant type dyes;however, the use of cationic dyes is preferred.

The chromic acid used should be at such a concentration that a 0.1 to 50percent aqueous solution of dichromate ion is obtained. Preferredconcentrations are l to 20 percent and most preferred are 5 to 15percent.

The chromic acid should also be heated; when it is used at roomtemperatures, the treating time is unduly prolonged. The acid ispreferably used at a temperature of 130 to 212 F.

The time of the acid treatment is not critical and it depends upon theconcentration and temperature of the acid. At higher concentrations orhigher temperatures, shorter times will be used. Thus at a temperatureof l60-l65 F., times of 20-25 minutes are generally required. Further,the time for this treatment will depend on whether individual fibers orfabrics are being treated, and also the type of fabric. Thus the time totreat a tightly woven fabric will be greater than that for a singlefiber. One skilled in the art can readily determine the best timing forhis particular fabric.

The treating material, aqueous chromic acid, is an acidic, aqueoussolution of dichromate ions.

The preferred source of the chromate ions is chromium trioxide, that isCrO or its hydrate chromic acid, H CrO or the dichromate H Cr- O Othersources of chromate ions are sodium, potassium, lithium or ammoniumdichromate. However, with the use of these latter compounds, anotheracid, such as sulfuric, should also be used. Further, with thesecompounds, they should be present in such amounts to provide the desiredconcentration of Cr 0, in the aqueous solution.

It has been found that the presence of sulfuric acid is a benefit insome instances, depending upon the dye or source of Cr O, to be used.Thus the chromic acid composition can contain 0 to 10 percent H 50preferably 0.5 to 5 percent, and most preferred 0.5 to 2 percent.Generally it is desirable not to use too much sulfuric acid in view ofthe effect of this acid on the strength of the glass fibers. Thus whenit is present it should be present in the approximate ratio of 10 partsCrO to one part H After the chromic acid treating step, the treatedglass fibers are washed in cold water to remove the excess acid. Priorto the treatment the glass fibers have a white color; after beingtreated with the chromic acid they will have a dark yellow color. Thewashing step removes the excess chromate ion, and the fibers will thenhave a light yellow color. This indicates the presence of residualchromate ions on the surface of the fibers.

The fibers can then be dyed with cationic (basic) or mordant type dyes,the cationic dyes being preferred. These dyes in some fashion hook upwith the glass fibers through the negatively charged surface of theresidual chromate ions and a good bond is obtained.

Again, although the Applicant does not intend to be bound thereto, it ishis belief that the chromate ions on the surface also act as a retarder"controlling the rate of dye absorption and as a result avoids blotching.Further, with the cationic type dyes, the chromium is removed from thefiber glass during the dyeing step. It is thought that the dye reducesthe Cr" present to Cr and the latter leaves the surface as the dyeattaches.

Exemplary of useful cationic dyes are the following:

Basic Green 3 Basic Violet 3 42555 Basic Vio1ct2 42520 Basic Green 142040 Basic Green 4 42000 Exemplary of useful mordant type dyes are thefollowing:

The dyes are applied as aqueous composition. The concentration and timefor dyeing are not critical to this process, and whatever is generallyused by the dye industry for the dye involved will be satisfactory.Generally high concentrations are avoided because they are wasteful ofdyes, and normally dilute solutions with longer dyeing times will beused.

After the dyeing step, the dyed fibers are rinsed and dried. The fibersat this time have dry cleaning resistance; however they are generallyovercoated with a material to give laundry resistance.

The overcoating material used is not critical and include such materialsas resins, plastics, elastomers, chrome complexes and the like can beused. Exemplary of useful overcoating materials are:

silanes of ethylene-methacrylic acid copolymers,

copolymers of methacrylic acid chrome complex and alkylacrylates.

Werner type chromium complexes, such as Quilon" (trademark of the DuPont Company), fluorinated chrome complexes such as Scotchguard(trademark ofMinnesota Mining and Manufacture, lnc.),butadiene-acrylonitrile latex,

thermosetting resins,

cationic long chain nitrogen compounds, such as Zelan" (trademark ofthedu Pont Company), organopolysiloxanes.

The dried fabric is generally placed in a solution of the overcoatingmaterial at room or elevated temperatures and allowed to react for ashort period of time. The excess solution is then removed and the fabricdried at elevated temperatures.

Subsequently, any of the conventional processes or operations of thefiber glass industry can be employed on the dyed fibers.

The final dyed fibers can be used for any of the conventional uses ofglass fibers and also areas wherein bright color fabrics and fabricswith good hand are desired, i.e., tablecloths, bedspreads, draperies,clothing and the like.

The invention will now be illustrated by the following examples.

EXAMPLE 1 A piece of heat cleaned (coronized) fibrous glass fabric isplaced in an aqueous solution of chromium trioxide percent by weight CrOat 160 F. for 25 minutes. The fabric is made of beta fibers, whichfibers have an average diameter of 3.8 microns. The fabric is thenremoved and the excess acid washed off with cold water. The treatedfabric is then placed in a dye bath containing 3 percent ofSevron" Blue50 dye (based on weight of fabric). The temperature of the dye bath israpidly increased from 74 C. to 212 F. and then maintained at 212 F. for30 minutes.

The fabric is removed and the excess dye washed offin cold water and thefabric is then dried at 266 F. The dried fabric is then placed in a lwt./vo1. percent of an olefinic copolymer containing pendant silanegroups, in Ferclene peechluroethylene solvent at 158 F. The fabric isremoved after 30 minutes. air dried for 5 minutes, and then oven driedat 266 F. for 45 minutes.

The resulting fabric is placed in a 0.5 percent soap solution at 130 F.for 30 minutes with agitation and there is essentially no loss of color.Another sample is tested in Perclene" to determine the fastness of thedyeing to drycleaning and it is rated as very good.

EXAMPLE 2 A piece of heat cleaned (coronized) fibrous glass fabric (betafiber of 3.8 micron diameter) is' placed in an aqueous solution ofchromium trioxide (10 percent by weight CrO at 160 F. for 25 minutes.The fabric is then removed and the excess acid washed off with coldwater. The treated fabric is then entered into a dye bath containing 2to 3 percent of Crystal Violet dye (based on weight of fabric). Thetemperature ofthe dye bath is rapidly increased from 74 F. to 212 F. andthen maintained at 212 F. for 30 minutes.

The fabric is removed and the excess dye washed off in cold water andthe fabric is then dried at 266 F. The dried fabric is then placed in a10 percent solution ofQuilon C (a Werner type chrome complex) for 5minutes at room temperature. The fabric is then dried at 266 F.

This results in a brightly colored fabric with good hand and resistanceto laundering and drycleaning.

EXAMPLE 3 A piece of heat cleaned (coronized) fibrous glass fabric (betafiber) is placed in an aqueous solution of chromium trioxide (10 percentby weight of CrO 7/1 weight ratio Gro /concentrated H 50 at 150 F. for15 minutes. The fabric is then removed and the excess acid washed offwith cold water. The treated fabric is entered into a dye bathcontaining 3 percent of Brilliant Green Crystals dye (based on weight offabric). The temperature of the dye bath is raised from 74 F. to 212 F.over a 20-minute period and then maintained at 212 F. for an additional60 minutes.

The fabric is removed and the excess dye washed offin cold water and thefabric dried at 230 F. The dried fabric is then placed in a 3 percentsolution of a methacrylato chromic chloride-methyl methacrylatecopolymer for 4 minutes at room temperature. The fabric is removed andair dried for 10 minutes then oven dried at 266 F. for 30 minutes. Theresulting fabric exhibits excellent dye retention after being washed for1 hour at 130 F. in a 0.5 percent soap solution.

EXAMPLE4 A piece of heat cleaned (coronized) fibrous glass fabric (betafiber) is placed in an acidified aqueous solution of potassiumdichromate (15% K Cr O and 2 percent concentrated H at 160 F. for 25minutes. The fabric is then removed and the excess acid washed off withcold water.

The treated fabric is then placed in a dye bath containing 3 percentofSevron" Yellow R dye (based on the weight of the fabric) and 0.5percent of a nonionic surface active agent and 1.0 percent glacialacetic acid. The temperature of the dye bath is rapidly increased from74 F. to 212 F. and then maintained at 212 F. for 30 minutes.

The fabric is removed and the excess dye is washed off in cold water andthe fabric dried at 266 F. The dried fabric is then placed in a 4percent solution ofZelan" (a cationic long chain nitrogen compound) at-1 15 F. for 5 minutes. The fabric is removed and dried at 230 F.

We claim:

1. A method for treating glass fibers comprising contacting glass fiberswith a 0.1 to 50 weight percent aqueous solution of chromic acidcontaining 0 to 10 weight percent of H 80, at a temperature of about to212 F. until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibers.

2. The process of claim 1 wherein the glass fibers are coronized priorto the treatment with the aqueous chromic acid solution.

3. A method for treating glass fibers comprising contacting glass fiberswith a 0.1 to 50 weight percent aqueous solution of chromic acidcontaining 0 to weight percent of H 80, at a temperature of about 130 to212 F. until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibers,washing said fibers, and dyeing said fibers with a cationic or mordanttype dye.

4. A method for treating glass fibers comprising contacting glass fiberswith a 0.1 to 50 weight percent aqueous solution of chromic acidcontaining 0 to 10 weight percent of H 80, at a temperature of about 130to 212 F. until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibers,washing said fibers, and dyeing said fibers with a cationic type dye.

5. A method for treating glass fibers comprising contacting glass fiberswith a 0.1 to 50 weight percent aqueous solution of chromic acidcontaining 0 to 10 weight percent of H 80 at a temperature of about 130to 212 F. until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibers,washing said fibers, dyeing said fibers with a cationic or mordant typedye, and coating with an overcoat material selected from the groupconsisting of chrome complexes, elastomeric materials, plasticmaterials, resinous materials, and organo-silanes.

6. Method for treating glass fibers comprising contacting glass fiberswith a 0.1 to 50 weight percent aqueous solution of chromic acidcontaining 0 to 10 weight percent of H 80 at a temperature of about 130to 212 F. until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibers,washing said fibers, dyeing said fibers with a cationic type dye, andcoating with an overcoat material selected from the group consisting ofchrome complexes, elastomeric materials, plastic materials, resinousmaterials, and organosilanes.

7. Glass fibers suitable for dyeing with cationic and mordant dyes beingprepared by treating glass fibers with a 0.1 to 50 weight percentaqueous solution ofchromic acid containing 0 to 10 weight percent of H80, at a temperature of about 130 to 212 F. until the surface area ofsaid fibers is increased and a chromium-containing material is depositedon the surface of the fibers.

8. Colored glass fibers being prepared by treating glass fibers with a0.1 to 50 weight percent aqueous solution of chromic acid containing 0to 10 weight percent of H at a temperature of about to 212 F. until thesurface area of said fibers is increased and a chromium-containingmaterial is deposited on the surface of the fibers, and then dyeing thefibers with a cationic or mordant type dye.

9. Colored glass fibers being prepared by treating glass fibers with a0.1 to 50 weight percent aqueous solution of chromic acid containing 0to 10 weight percent of H 80, at a temperature of about 130 to 212 F.until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibers,and then dyeing the fibers with a cationic or mordant type dye andcoating the dyed fibers with a protective material which gives themlaundry resistance.

10. Colored glass fibers being prepared by treating glass fibers with a0.1 to 50 weight percent aqueous solution of chromic acid containing 0to 10 weight percent of H 80. at a temperature of about 130 212 F. untilthe surface area of said fibers is increased and a chromium-containingmaterial is deposited on the surface of the fibers, and then dyeing thefibers with a cationic type dye.

ll. Colored glass fibers being prepared by treating glass fibers with a0.1 to 50 weight percent aqueous solution of chromic acid containing 0to 10 weight percent of H 80, at a temperature of about 130 to 212 F.until the surface area of said fibers is increased and achromium-containing material is deposited on the surface of the fibersand then dyeing the fibers with a cationic type dye and coating the dyedfibers with a protective material which gives them laundry resistance.

a r t a a

2. The process of claim 1 wherein the glass fibers are coronized priorto the treatment with the aqueous chromic acid solution.
 3. A method fortreating glass fibers comprising contacting glass fibers with a 0.1 to50 weight percent aqueous solution of chromic acid containing 0 to 10weight percent of H2SO4 at a temperature of about 130 to 212* F. untilthe surface area of said fibers is increased and a chromium-containingmaterial is deposited on the surface of the fibers, washing said fibers,and dyeing said fibers with a cationic or mordant type dye.
 4. A methodfor treating glass fibers comprising contacting glass fibers with a 0.1to 50 weight percent aqueous solution of chromic acid containing 0 to 10weight percent of H2SO4 at a temperature of about 130 to 212* F. untilthe surface area of said fibers is increased and a chromium-containingmaterial is deposited on the surface of the fibers, washing said fibers,and dyeing said fibers with a cationic type dye.
 5. A method fortreating glass fibers comprising contacting glass fibers with a 0.1 to50 weight percent aqueous solution of chromic acid containing 0 to 10weight percent of H2SO4 at a temperature of about 130 to 212* F. untilthe surface area of said fibers is increased and a chromium-containingmaterial is deposited on the surface of the fibers, washing said fibers,dyeing said fibers with a cationic or mordant type dye, and coating withan overcoat material selected from the group consisting of chromecomplexes, elastomeric materials, plastic materials, resinous materials,and organo-silanes.
 6. Method for treating glass fibers comprisingcontacting glass fibers with a 0.1 to 50 weight percent aqueous solutionof chromic acid containing 0 to 10 weight percent of H2SO4 at atemperature of about 130 to 212* F. until the surface area of saidfibers is increased and a chromium-containing material is deposited onthe surface of the fibers, washing said fibers, dyeing said fibers witha cationic type dye, and coating with an overcoat material selected fromthe group consisting of chrome complexes, elastomeric materials, plasticmaterials, resinous materials, and organosilanes.
 7. Glass fiberssuitable for dyeing with cationic and mordant dyes being prepared bytreating glass fibers with a 0.1 to 50 weight percent aqueous solutionof chromic acid containing 0 to 10 weight percent of H2SO4 at atemperature of about 130 to 212* F. until the surface area of saidfibers is increasEd and a chromium-containing material is deposited onthe surface of the fibers.
 8. Colored glass fibers being prepared bytreating glass fibers with a 0.1 to 50 weight percent aqueous solutionof chromic acid containing 0 to 10 weight percent of H2SO4 at atemperature of about 130 to 212* F. until the surface area of saidfibers is increased and a chromium-containing material is deposited onthe surface of the fibers, and then dyeing the fibers with a cationic ormordant type dye.
 9. Colored glass fibers being prepared by treatingglass fibers with a 0.1 to 50 weight percent aqueous solution of chromicacid containing 0 to 10 weight percent of H2SO4 at a temperature ofabout 130 to 212* F. until the surface area of said fibers is increasedand a chromium-containing material is deposited on the surface of thefibers, and then dyeing the fibers with a cationic or mordant type dyeand coating the dyed fibers with a protective material which gives themlaundry resistance.
 10. Colored glass fibers being prepared by treatingglass fibers with a 0.1 to 50 weight percent aqueous solution of chromicacid containing 0 to 10 weight percent of H2SO4 at a temperature ofabout 130 212* F. until the surface area of said fibers is increased anda chromium-containing material is deposited on the surface of thefibers, and then dyeing the fibers with a cationic type dye.
 11. Coloredglass fibers being prepared by treating glass fibers with a 0.1 to 50weight percent aqueous solution of chromic acid containing 0 to 10weight percent of H2SO4 at a temperature of about 130 to 212* F. untilthe surface area of said fibers is increased and a chromium-containingmaterial is deposited on the surface of the fibers and then dyeing thefibers with a cationic type dye and coating the dyed fibers with aprotective material which gives them laundry resistance.